Related papers: Vacuum Structure and Chiral Symmetry Breaking
Dynamical chiral symmetry breaking is a nonperturbative phenomenon that may be studied using QCD's gap equation. Model-independent results can be obtained with a nonperturbative and symmetry preserving truncation. The gap equation yields…
Electroweak symmetry can be naturally broken by observed quark and gauge fields in various extra-dimensional configurations. No new {\it fundamental} fields are required below the quantum gravitational scale ($\sim$ 10 - 100 TeV). We…
It is well-known that chiral symmetry breaking ($\chi$SB) in QCD with $N_{f}=2$ light quark flavours can be described by orthogonal groups as $O(4) \to O(3)$, due to local isomorphisms. Here we discuss the question how specific this…
Exploiting the recent lattice results for the infrared gluon propagator with light dynamical quarks, we solve the gap equation for the quark propagator. We thus model the chiral symmetry breaking mechanism with increasing number of flavours…
After noting the well known similarity of the minimal electro-weak Higgs sector with the linear sigma model for the pion and the sigma, it is found that a small mixing term between the two models generates a pion mass. Although the…
We explore the phase structure of a chiral model of constituent quarks and gluons implementing scale symmetry breaking at finite temperature and chemical potential. In this model the chiral dynamics is intimately linked to the trace anomaly…
Due to its light mass of order Lambda_QCD, the strange quark can play a special role in Chiral Symmetry Breaking (ChSB): differences in the pattern of ChSB in the limits N_f=2 (m_u,m_d->0, m_s physical) and N_f=3 (m_u,m_d,m_s->0) may arise…
The SU(3) breaking effects due to light quark masses on heavy meson masses, decay constants ($F_{D}, F_{D_{s}}$) and the form factor for semileptonic $\overline{B}\rightarrow D^{(\ast)} l\bar{\nu}_{l}$ transitions are formulated in chiral…
We review the chiral spin symmetry, which is a symmetry of the color charge and of the confining electric part of QCD. Observation of this symmetry in the vacuum upon truncation of the near-zero modes of the Dirac operator implies that the…
Using the heavy quark effective theory, chiral structure of the $b\rightarrow c$ charged current can be determined by the semileptonic $\Lambda_b$ decay with satisfactory theoretical accuracy. We define an asymmetry which is sensitive to…
In the physical vacuum of QCD, the energy density of light-quark fields strongly coupled to slowly varying gluon fields can be negative, and so a condensate of pairs of quarks and antiquarks of nearly opposite momenta forms which breaks…
It is the purpose of the present manuscript to emphasize those aspects that make the scalar sector with vacuum quantum numbers rather unique. Chiral symmetry is the basic tool for our study together with a resummation of Chiral Perturbation…
We consider a U(1) gauge theory, minimally coupled to a massless Dirac field, where a higher-derivative term is added to the pure gauge sector, as in the Lee-Wick models. We find that this term can trigger chiral symmetry breaking at low…
We study chiral symmetry breaking in QED when a uniform external magnetic field is present. We calculate higher order corrections to the dynamically generated fermion mass and find them to be small. In so doing we correct an error in the…
We use a variational procedure to study finite density QCD in an approximation in which the interaction between quarks is modelled by that induced by instantons. We find that uniform states with conventional chiral symmetry breaking have…
We report on a mean-field study of spontaneous breaking of chiral symmetry for Dirac fermions with contact interactions in the presence of chiral imbalance, which is modelled by nonzero chiral chemical potential. We point out that chiral…
Dynamical properties of gauge theories with light flavor quarks are studied in a dual supergravity by adding a D7-brane probe into the AdS background deformed by the dilaton. By estimating the vev of flavor quark-bilinear in both the…
Spontaneous chiral symmetry breaking in QCD with massless quarks at infinite volume can be seen in a finite box by studying, for instance, the dependence of the chiral condensate from the volume and the quark mass. We perform a feasibility…
The restoration of chiral symmetry at finite density and/or temperature is investigated in a wide class of one-gluon exchange models in the instantaneous approximation. If the effective quark interaction is less divergent than $1/k^2$ for…
QCD sum rules serve as tools to investigate changing hadronic properties in a hot and/or dense nuclear medium. The role of chiral symmetry breaking and restoration effects in a medium can be addressed also in the heavy-light meson sector.…